Integrating heat pumps into CHP plants to support CO2 capture

Abstract

Integrating CO 2 capture into combined heat and power (CHP) plants reduces heat and electricity generation. Heat pumps (HPs) can be utilized to recover waste heat for solvent regeneration or district heating (DH). However, no study compares different ways of utilizing recovered heat. Therefore, this study evaluated the performance of a HP-integrated CHP plant with CO 2 capture. Four cases were considered, Case 1 (reference case 1): without CO 2 capture; Case 2 (reference case 2): with CO 2 capture and no HPs; Case 3: with CO 2 capture and using HPs to recover heat for DH; and Case 4: with CO 2 capture and using HPs to recover heat for solvent regeneration. Using real operating data from a waste-fired CHP plant (50 MW e , 110 MW th ), results demonstrated that, in Case 2 (cf. Case 1), maximum 81.6% of CO 2 was captured at a cost of 62.6% reduction in net electricity generation. In Case 3, 45.3% of the DH demand was covered by HP recovered heat, amounting 375.8 GWh/year. In Case 4, 78.3% of the heat required for CO 2 capture was supplied by HP recovered heat, reaching 445.1 GWh/year. While 90% of CO 2 was captured in Cases 3 and 4, the annual net electricity generation was reduced by 64.5% and 37.1%, respectively. Additionally, given current carbon trading prices, CO 2 capture was not economically feasible and that system’s internal heat recovery by HPs is not economically feasible, either.

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